Various wind-driven generating plant constructions are known and the essential differentiating feature thereof is the arrangement of the rotation axis.
In the case of wind-driven generating plants with horizontal rotation axis, particularly in the case of large plants, costly constructional measures are required due to the weight of the tower, which carries the inner cell, hub, gear and generator, so that such plants require a high capital expenditure relative to the energy yield. Wind-driven generating plants with a vertical rotation axis according to Darrieus' principle, in which the lifting forces of the blade profiles are used for converting kinetic energy into rotation energy, only have use advantages compared with rotors having a horizontal rotation axis in the case of lower capacities. However, they require special starting aids, such as e.g. an electric motor or a Savonius rotor. However, due to the construction the wind capture cross-section related to the blade length and the efficiency is greater in the case of vertical rotors than in the case of horizontal rotors. To obtain the same efficiency as horizontal rotors, vertical rotors require a larger structure and consequently increased costs. For the utilization of the energy contained in land and sea winds on water surfaces, it has long been known to equip ships or boats with sails. The craft is advanced through the skillful utilization of the wind force or power, which can either take place on the wind, before the wind, leading the wind or with a beam wind. As a function of the rigging, it is possible to sail more or less close against the wind. The disadvantage is that the handling of the sails requires a large crew. Attempts have therefore been made to use rigid blade or wind surfaces as sails, but this is very expensive from the material standpoint and has also not led to satisfactory results.